The Culture Secretary waded into the row between Tube chiefs and the RMT with a scathing attack on the union. "The RMT's plans to strike duringWimbledon looks like nothing more than a cynical attempt to ruin one of our great sporting events," he told The Standard.

"Thousands of fans will be left disappointed if these blackmail plans go ahead." He hit out as it emerged that Tube bosses offered to buy-off Arwyn Thomas, the sacked Northern line driver at the centre of four strikes due to start this Sunday. He turned down the cash, insisting he is reinstated.

The RMT union has denied that the strikes, spread over seven days, are designed to disrupt the tennis championships.

RMT leaders today appealed to 1,500 driver members to support the strikes.

RMT boss Bob Crow rejected Mr Hunt's claim."The RMT isn't blackmailing anyone. We've had a fully legal ballot and all we are doing is standing shoulder to shoulder with a member who has been picked on and victimised by an LU management prepared to flout employment law and ignore the judges words in the Employment Tribunal.

"That's simply standing up for basic workers rights and is clearly too much for old-school Tory right-wingers like Jeremy Hunt to stomach."Thomas, who has 30 years service, was dismissed for alleged abusive behaviour towards colleagues - a charge denied robustly.

An Employment Tribunal hearing has been adjourned until the end of the month.Efforts to reach agreement between London Underground (LU) and the RMT ahead of the tribunal decision have failed.

Steve Hedley, the RMT's London transport regional organiser, today wrote to all the union's driver member being balloted for action. The RMT insists the "real reason" behind the sacking is because Thomas is an admitted union activist who helped organise strikes last year over job cuts.

Mr Hedley states: "We must demand justice for Arwyn Thomas and send a clear message to LU that victimisation of trade union reps and activists will not be tolerated by our members.

"We cannot stand idly by and wait for a full Employment Tribunal to decide Arwyn's fate."He said LU had persistently refused to give Thomas his job back despite him being granted "interim relief" by an earlier tribunal hearing. This meant LU had to continue to pay him his full £45,000 a year salary while he remained at home pending the full hearing.

"In the event they (LU) were only prepared to offer him some him some money which he, as a very principled trade unionist, has rejected," said Mr Hedley. He described Thomas as having an "exemplary record" with LU during 30 years of service. "There is not so much as a local disciplinary for attendance or lateness on his record."

Neither the RMT nor LU would say how much Thomas was offered. A LU spokesman said: "There were discussions between the legal representives to try and resolve this issue ahead of the tribunal." These effors failed.

On charges the strikes have been timed to hit Wimbledon, a spokesman for Bob Crow, the RMT leader, said: "Absolutely not - our dispute is with LU not tennis fans."

The Championships run from 20 June to 3 July.The strikes begin at 9.01pm on Sunday, 19 June.That will last six hours and threatens the Monday, 20 June, morning peak.

This will be followed by walkouts beginning 9.01 pm Monday 27 June lasting until until 11.59 Tuesday 28 June; this will mean an early run down of services Monday evening and cripple the Tuesday morning peak.

The third strike starts 12.00 Wednesday 29 June until 11.59 Thursday 30 June; this will cripple Wednesday evening peak and Thursday morning peak.

The fourth strikes runs from 12.00 Friday 1 July and ends same day 9pm; this will again cripple the evening peak.